Move c_api_tfrt to core/tfrt/eager (NFC)

c_api_tfrt is an implementation of the C API, so it should not be in c/eager/.
Move it to core/tfrt/eager to mirror the setup for the current TF runtime
directory core/common_runtime/eager.

PiperOrigin-RevId: 310590751
Change-Id: I6840756c321c29eec2a6b648c3484ec4fc8bd46e

tensorflow/c/eager/BUILD

@@ -16,7 +16,6 @@ load(
     "//tensorflow/core/platform:build_config_root.bzl",
     "tf_cuda_tests_tags",
 )
-load("@local_config_cuda//cuda:build_defs.bzl", "if_cuda")
 
 package(
     licenses = ["notice"],  # Apache 2.0
@@ -609,7 +608,6 @@ filegroup(
         ],
         exclude = [
             "c_api_experimental.cc",
-            "*c_api_tfrt*",
             "*test*",
             "*dlpack*",
         ],

tensorflow/c/eager/c_api.cc

@@ -38,7 +38,7 @@ limitations under the License.
 #include "tensorflow/c/eager/tfe_tensorhandle_internal.h"
 #include "tensorflow/c/tf_tensor_internal.h"
 #ifdef PLATFORM_GOOGLE
-#include "tensorflow/c/eager/c_api_tfrt.h"
+#include "tensorflow/core/tfrt/eager/c_api_tfrt.h"
 #endif
 #include "tensorflow/core/common_runtime/device.h"
 #include "tensorflow/core/common_runtime/eager/context.h"